Exploring the Solar System and Astronomy

Solar System

• Composed of the Sun, eight planets, and various celestial objects.
• Inner planets: Mercury, Venus, Earth, Mars.
• Outer planets: Jupiter, Saturn, Uranus, Neptune.

Definition of a Planet

• A large sphere in space orbiting a star.
• Planet characteristics: rotation on axis and revolution around the Sun.
• Size varies; some are smaller than Earth, while others are larger.

Celestial Objects

• Stars: Hot, glowing gas balls; the Sun is a medium-sized star.
• Asteroids: Rock or metal fragments.
• Comets: Composed primarily of ice, along with dust and rock.
• Meteors: Small debris from comets or asteroids.

Telescopes

• Instruments that gather light to magnify distant objects.
• Types:
  • Hubble Space Telescope: Orbits Earth, captures images regularly.
  • Radio telescopes: Detect radio waves, converting them into images using computers.

Historical Discoveries

• Copernicus (1543) proposed that the Sun is the solar system's center.
• Galileo used telescopes in 1609 to provide evidence of Earth's orbit around the Sun.

Constellations and Galaxies

• Constellations: Groups of stars forming identifiable patterns; names derive from imagined shapes.
• Galaxy: A vast collection of stars; the solar system resides in the Milky Way galaxy.

States of Matter

• Matter: Substance that occupies space and has mass.
• States:
  • Solid: Defined shape and volume (e.g., book, cup).
  • Liquid: Defined volume but variable shape; conforms to its container (e.g., water, juice).
  • Gas: No defined shape or volume; expands to fill its container (e.g., helium in a balloon).

Matter Vocabulary

• Mass: Amount of matter in an object.
• Volume: Space an object occupies.
• Phase changes:
  • Melting: Solid to liquid with heat.
  • Evaporating: Liquid to gas with heat.
  • Freezing: Liquid to solid with heat loss.
  • Condensing: Gas to liquid with heat loss.

Elements and the Periodic Table

• Elements: Fundamental components of matter; over 100 recognized.
• Periodic table: Chart organizing known elements by their symbols.

Glenn Seaborg and Plutonium

• Created plutonium (atomic number 94) in 1940, important for nuclear weapons and energy.
• Identified several heavy elements and their isotopes, contributing significantly to chemistry.

Atoms

• Atoms: Smallest units of elements; identical within the same element.
• Invisible to the naked eye; smaller than dust particles.
• Studied using electron microscopes, which can examine these minute structures effectively.